This invention provides an improved process for preparing intermediates useful in the preparation of tricyclic compounds known as antihistamines and as inhibitors of farnesyl protein transferase (FPT). In particular, the compounds of this invention are useful in the preparation of antihistamines such as those disclosed in U.S. Pat. Nos. 4,282,233 and 5,151,423, and of FPT inhibitors disclosed in International Application No. PCT/US96/19603, filed Dec. 19, 1996.